Answer:
{0, 150} degrees
Step-by-step explanation:
Given 2cos^2x-cost-1=0, let's simplify this problem by temporarily replacing cos x with y:
2y^2 - y -1 = 0
This can be solved by factoring: (2y + 1)(y - 1) = 0. From this we get two solutions: y = -1/2 and y = 1.
Remembering that we let y = cos x, we now solve:
cos x = -1/2 and cos x = 1.
Note that cos x = 1 when x = 0 and the "adjacent side" coincides with the hypotenuse.
cos x = -1/2 when the hypotenuse is 2 and the "adjacent side" is -1. This has two solutions between 0 and 360 degrees: 150 degrees and 270 degrees.
Four answer choices are given. Both (a) (0 degrees) and (b) (150 degrees) satisfy the original equation. Thus, the solution set is {0, 150} (degrees).
Answer:
-4
Step-by-step explanation:
x^2+4x+5=0
a=1,b=4^1 C=5
4^2-4×1×5
-4
Answer:
1. 1/2
2. 4/5
3. 9/10
4. 3/4
5. 12/25
6. 18/25
Step-by-step explanation:
Step-by-step explanation:
once the level of medicine reaches a value, where 30% are 23mL (so, whatever is lost, is immediately replaced again), that is then the long run value for the amount of the drug in the patient's body.
so,
30% = 23 mL
1% = 30%/30 = 23/30 = 0.766666666...
100% = 1%×100 = 0.766666666... × 100 = 76.666666...
so, once the level reaches 76.666666... mL in the body, it will remain constant, as the daily filtered out 30% are 23 mL, and the daily add-on is also 23 mL.
so, the answer is
76.667 mL
I only know D. but I'll try to figure out the rest too. D. 9 years old
